Shareholders' Equity, Dividend Restrictions and Other Regulatory Matters (Detail) - Components of Accumulated Other Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Balance	$ (2,844)	$ (2,684)	$ 2,476	$ 4,850	$ 3,933
Net change in other comprehensive income	(5,320)	160	(2,374)	917
Unrealized gain (loss) on securities available for sale [Member]
Balance	(1,889)	(1,709)	3,431	5,545	4,449
Net change in other comprehensive income	(5,320)	180	(2,114)	1,096
Change in pension liability [Member]
Balance	(955)	(975)	(955)	(695)	(516)
Net change in other comprehensive income		$ (20)	$ (260)	$ (179)